The present invention relates to the liquid supply assemblies that supply mixtures of component liquids to be sprayed (e.g., paint) to liquid spraying devices or spray guns, and in one aspect, to the indicia on such assemblies by which the mixtures of component liquids to be sprayed by such devices are measured in predetermined ratios.
Various liquid supply assemblies have been described for supplying mixtures of component liquids to be sprayed to gravity fed liquid (e.g., paint) spraying devices or spray guns, including the supply assembly including a collapsible liner that is described in International Publication Number WO 98/32539 of Jul. 30, 1998, the content whereof is incorporated herein by reference. The liquid supply assembly described in WO 98/32539 includes a container of stiff polymeric material comprising a frusto conical side wall and a bottom wall at a bottom end of the side wall with an opposite top end of the side wall defining an opening into a cavity in the container, and a flexible liner within that cavity, which liner corresponds in shape to an inner surface of the container, and has an annular lip along the top end of the side wall that defines an opening into a cavity in the liner. That liquid supply assembly further includes an adapter assembly comprising a central portion having a through opening that is adapted to engage the inlet port of the gravity fed liquid spraying device, a transverse portion including a peripheral part adapted for engagement within the flexible liner adjacent the top end of the container, and means for releasably securing the flexible liner around that peripheral part of the adapter assembly. The flexible liner within the cavity in the container can be used as a receptacle for measuring and mixing two or more component liquids for the mixture to be sprayed, and markings or indicia are provided on the side of the container that enable the volume of the contents of the container to be determined, which can facilitate measuring the needed amounts of those component liquids.
Automotive paint companies (e.g., DuPont, PPG, BASF, Sikkens) specify mix ratios for the component liquids in their refinishing materials (e.g., paints, primers, clearcoats), many of which mix ratios are distinctly different, and require accurate measuring of the different component liquids to achieve desired results. The automotive paint companies recommend weighing the component liquids in the mix ratios using an electronic scale. It is estimated, however, that less than 25% of the automobile refinishing shops in the U.S.A. use that method. The component liquids in the mix ratios can be measured to obtain the desired ratio using the appropriate xe2x80x9cmix stickxe2x80x9d, which is a precision metal ruler with various mix ratios printed on it (e.g., 1:1, 2:1, 3:1:1, 4:1:1, 100:50:30, 5:1:2, 100:100:10, etc). The mix stick is stood upright in an appropriate container with vertical sides, and the component liquids are added in the appropriate ratio using marks on the mix stick to determine the amounts of the liquids to be added.
Most automobile refinishing shops, however, are believed to measure the component liquids to obtain the desired mix ratio using disposable mixing cups of stiff visually transparent polymeric material that bear indicia on their side walls indicating the levels to which a plurality of different component liquids should be sequentially poured into the cup to achieve the desired mix ratio between them. U.S. patent application Ser. No. 09/374,794 filed Aug. 16, 1999, describes a liquid supply assembly adapted for use on a gravity fed liquid spraying device that includes that disposable mixing cup by providing (1) an adapter assembly comprising a central portion having a through opening that is adapted to engage the inlet port of the gravity fed liquid spraying device, and a transverse portion including a peripheral part adapted for sealing engagement within the top end of the disposable mixing cup; together with (2) a tapered removable pin (e.g., a pin of the type sometimes called a xe2x80x9cpush pinxe2x80x9d) that is inserted through the side wall of the disposable mixing cup adjacent its bottom wall and can be removed to provide vacuum relief for the liquid supply assembly.
While the indicia provided on either the container of the liquid supply assembly described in WO 98/32539 or on the disposable cup of the liquid supply assembly described in U.S. patent application Ser. No. 09/374,794 could be used for making a mixture of two or more component liquids to be sprayed by a gravity fed liquid spraying device, it is not possible to provide on either that container or mixing cup all of the different indicia that might be needed to mix all of the different ratios of different component liquids that might be desired by operators of such gravity fed liquid spraying devices. Thus, several different containers or mixing cups bearing different indicia must be made and provided. We estimate that at least ten different containers or mixing cups would be needed just to properly cover the majority of mix ratios needed for paint component liquids commercially available from DuPont, PPG, BASF, or Sikkens.
The present invention provides a liquid supply assembly for use with liquid spraying devices that, like the liquid supply assemblies described above, provides indicia by which component liquids for mixtures of liquids to be sprayed by such devices are measured to provide predetermined ratios, but which affords conveniently providing indicia that facilitates measuring many more of the different ratios of different component liquids that might be desired by operators of such liquid spraying devices than when such indicia are provided on the containers or mixing cups as described above.
According to the present invention there is provided a liquid supply assembly that, like the liquid supply assembly described in International Publication Number WO 98/32539, comprises (1) a container of stiff polymeric material comprising a side wall, and a bottom wall extending across the bottom end of the side wall, the container having an inner surface defining a cavity in the container, and a top end of the side wall defining an opening into the cavity, a portion of the inner surface along the side wall having the shape of a conical frustum and increasing in diameter from the bottom end toward the top end of the side wall; (2) a visually transparent flexible liner within the cavity in the container, which liner has an outer surface corresponding in shape to the inner surface of the container, an inner surface defining a cavity in the liner, and an annular lip along the top end of the side wall defining an opening into the cavity in the liner; and (3) indicia that provide information about the contents of the container.
Unlike the liquid supply assembly described in International Publication Number WO 98/32539, however, the indicia in the present invention are provided on an indicating sheet of resiliently flexible polymeric material positioned between the side wall of the container and the flexible liner, which indicating sheet conforms in shape to the inner surface of the container along the side wall, is accurately positioned with respect to the liner and the side wall, and bears such indicia by which the amount of a liquid within the container can be measured. That indicia can indicate the levels to which a plurality of different component liquids can be sequentially poured into the cavity in the flexible liner to achieve a predetermined ratio between the component liquids.
The use of the indicating sheet allows a person to prepare any one of many different ratios of different component liquids that might be desired by operators of liquid spraying devices by selecting an appropriate indicating sheet from a set of indicating sheets that together provide the indicia needed for preparing the majority of mix ratios needed for component liquids commercially available from major manufacturers. If different indicia is needed for use in preparing a different mix ratio of component liquids (e.g., an unusual or new paint mixture or the like), a new indicating sheet providing such indicia can be economically made and provided to meet that need.
To use the liquid supply assembly the indicating sheet of resiliently flexible polymeric material is positioned along the inner surface of the container, and the flexible liner is positioned in the container with the indicating sheet between the container and the liner where it will conform in shape to the inner surface of the side wall of the container and where the indicia on the indicting sheet will indicate the levels to which a plurality of different component liquids can be sequentially poured into the cavity in the flexible liner to achieve a predetermined ratio between those liquids for a material to be sprayed. Component liquids are then sequentially poured into the cavity in the liner to achieve a predetermined ratio between the component liquids indicated by the indicia on the indicating sheet, after which the component liquids are thoroughly mixed. The container and flexible liner containing the mixed component liquids can then be attached to a liquid spraying device by an adapter assembly that comprises a central portion having a through opening that is adapted to engage the inlet port of the gravity fed liquid spraying device, a transverse portion including a peripheral part adapted for engagement within the flexible liner adjacent the top end of the container, and means for releasably securing the flexible liner around that peripheral part of the adapter assembly.
A plurality of indicating sheets of resiliently flexible polymeric material adapted to conform in shape to the inner surface of the container may be provided, each of which indicating sheets has the same physical shape and structure but bears different indicia that, when the indicating sheet is positioned along the inner surface of the container between the container and the liner, will indicate the levels to which a plurality of different component liquids can be sequentially poured into the cavity in the liner to achieve different predetermined ratio between the liquids. A user of the liquid supply assembly will have to select an appropriate one of those indicating sheets to be positioned along the side wall of the container to use the assembly.
The container, indicating sheet and liner can all be transparent and the indicating sheet can be positioned along the inner surface of the container so that the indicia and liquid level in the liner can be seen through the side wall of the container. Alternatively, only the liner needs to be transparent and the indicating sheet can be positioned along the inner surface of the container so that the indicia can be read and the liquid level in the liner can be seen looking down through the open end of the liner. This approach provides the advantage when transparent liquids are being measured that the indicia on the indicating sheet below the level of liquid in the liner will visually disappear because of total internal reflection of incident light at the interface between the liner and a layer of air between the liner and the indicating sheet due to the indexes of refraction of the liquid and liner material at angles of incidence to the liquid surface of less than about 60 degrees, which are the angles of incidence at which the liquid level is normally observed. Such disappearance of the indicia on the indicating sheet below the level of liquid in the liner makes it quite easy to align the liquid level with a desired indicia on the indicating sheet.